Degradation of collagens and non-collagenous components of the glomerular extracellular matrix is believed to play an important role in the turnover of normal glomerular basement membranes, and in the pathogenesis of glomerulosclerosis. A new method combining microdissection of human glomeruli and competitive PCR has been utilized to examine glomeruli isolated from nephrectomy specimens. This method allows the detection of cDNA molecules in individual glomeruli, because of a detection range in the range of 10-4 attomoles. Preliminary results from glomeruli isolated from human nephrectomies indicate that the method is sensitive, reproducible, and allows comparison between patients.